A repeater is a combination transmitter and receiver that is used to extend the effective range of a transmitter. The repeater receives a signal at a particular frequency and power level, and rebroadcasts the signal at a higher power level. This allows broadcast signals to extend greater distances and can fill holes in coverage due to shielding from obstacles.
Typical prior art methods receive one frequency and retransmit at a second frequency. These methods are effective at eliminating spillover but require more of the spectrum to be used.
U.S. Pat. Nos. 6,430,391, and 6,768,900, both entitled “DUPLEX SATELLITE COMMUNICATION USING A SINGLE FREQUENCY OR PAIR,” discloses a system using a pair of frequencies. Two ground stations use the same frequencies, which creates interference. The system records the outgoing signal from at least one of the ground signal, and subtracts the outgoing signal to eliminate its interference. The system prerecording of signals and a time lag while the prerecorded signal is subtracted. The present invention is not limited in either regard. U.S. Pat. Nos. 6,430,391, and 6,768,900 are hereby incorporated by reference into the specification of the present invention.
Other methods use a single frequency to receive and retransmit the signal. These methods can suffer from oscillation.
U.S. Pat. No. 4,317,217, entitled “TAG GENERATOR FOR A SAME-FREQUENCY REPEATER,” discloses a method of adding a tag to the output signal. A tagged signal of variable amplitude and phase is added to the received signal to cancel the tag. The invention requires complex electronics to add and remove the tag. The present invention is not limited in this regard. U.S. Pat. No. 4,317,217 is hereby incorporated by reference into the specification of the present invention.
U.S. Pat. No. 4,383,331, entitled “METHOD AND MEANS OF PREVENTING OSCILLATIONS IN A SAME-FREQUENCY REPEATER,” discloses a method of adding a tag to the signal to be rebroadcast. Each subsequent repeater in the system includes a system of removing the previously applied tag. A phase adjustment and a time lag are introduced into the rebroadcast signal. The invention requires complex electronics to add the tag, remove the tag, and creates a time lag. The present invention is not limited in either regard. U.S. Pat. No. 4,383,331 is hereby incorporated by reference into the specification of the present invention.